DEPLOYMENT AND HEALING OF AN EPTFE ENCAPSULATED STENT ENDOGRAFT IN THE CANINE AORTA

This study evaluated deployment mechanics and long-term healing of an endoluminally placed stent/graft in normal canine aortas. The endolumi nal grail(ELG) consisted of a 8,5cm segment of expanded polytetrafluor oethylene (ePTFE) graft material (Impra, Inc., Tempe, AZ) encapsulatin g a series of six Palmaz P-128 stents (Johnson & Johnson Interventiona l Incorporated, New Brunswick, NJ) along the length of the graft, The prostheses were deployed via the femoral artery using a 14Fr delivery system that contained a balloon catheter to expand the ELG in the infr arenal aorta. Twenty-one prostheses were deployed and evaluated at 1 w eek (n = 3), 1 month (n=3), 3 months (n=3), 6 months (n=9), and 1 year (n=3). Dimensions of the infrarenal aorta were determined with intrav ascular ultrasound (IVUS) and angiography prior to deployment of devic es. Real-time fluoroscopy and IVUS were used to monitor device deploym ent with both imaging modalities repealed following implantation. Gros s inspection and microscopic evaluation was performed on the explanted specimens following in vivo evaluation by CT scan, IVUS, and angiogra phy prior to retrieval of the specimens. The prostheses were easily de ployed from the femoral access site. Oversizing of the deployment ball oon compared to the aortic diameter was necessary to accommodate the 1 0% device recoil observed following balloon deflation, however, all de vices were seated against the aortic wall as evidenced by IVUS. At exp lant, all devices ware widely patent with limited luminal thrombosis o bserved in four specimens (19%). Devices were well-incorporated by cel lular ingrowth into the ePTFE with the formation of neointima. No devi ce migration or postdeployment recoil was observed, ePTFE graft materi al between stents protruded slightly into the vessel lumen accounting for a 10% luminal reduction. Fully supported ELG's consisting of ballo on expandable stents encapsulated in ePTFE are easily deployed using a low-profile delivery system. Specimens demonstrated uniform long-term patency and healing up to 1 year in a canine aortic model. Those prel iminary findings support further study of this fully supported prosthe sis in the treatment of arterial disease.